In a 10 inch frying pan heat olive oil over medium heat. Add onions and saute until soft approximately 10 minutes.
Stir in minced garlic and cook for another minute then set pan aside to cool.
In a large bowl grate the carrot.
To the bowl add ground beef, ground turkey, bread crumbs, parmesan cheese, egg, salt, pepper and reserved onion mixture.
With your hands mix all ingredients together until it is consistent - you might need to help kids with this step.
Rolling between your 2 palms form meat mixture into small meatballs approximately 2 cm in size. Use approximately 1/3 of the mixture for these meatballs to be added to your soup.
At this point you should begin your soup preparation. Once the soup is simmering you can make additional meatballs of a larger size to be used in meatball subs or pasta.
To cook meatballs you can bake them on a large baking sheet at 400 degrees for approximately 20 minutes stirring after 10 minutes.
To cook meatballs in a marinara sauce, first bring the sauce to a boil, add meatballs and cover. Simmer this sauce for 45 minutes to one hour. Meatballs can be tested and should register 165 degrees in the centre.